Reynolds stress decay modeling informed by anisotropically forced homogeneous turbulence*

The Reynolds-averaged Navier-Stokes equations are popular for predicting complex turbulent flows due to their computational affordability and ability to estimate quantities of engineering interest. These equations, however, require proper closure models to treat unclosed terms. Here, we consider the terms responsible for decay of the Reynolds stresses in the six Reynolds stress transport equations. Using anisotropic forcing of the momentum equations, we access states of turbulence anisotropy traditionally not probed in a triply periodic domain and then perform robust selection of model forms and model coefficients to capture the decay terms. Our optimal model extends to cubic terms when expressed in terms of the principal coordinate Reynolds stresses. We demonstrate improved accuracy in predicting simulation data compared to extant models from the literature.